This application claims priority to French patent application FR 01 03 669 filed Mar. 19, 2001.
The invention concerns a vehicle window lifter mechanism, and more particularly a window lifter comprising a cable tensioning device.
Document DE-A-32 01 098 discloses a window lifter mechanism. This window lifter mechanism comprises a guide rail, a slider supporting a window glass and slidably mounted on the guide rail, cable redirection means provided at each end of the guide rail and a winding drum linked to the slider by at one cable passing over the cable redirection means. This type of window lifter is currently used in the automobile industry. A cable-winding drum is driven in rotation either by a handle, or by a motor and speed reduction gear to raise and lower the vehicle window. During this operation, one of the cables is wound onto the drum while the other cable is unwinding. In operation, the cable is kept tensioned to reduce angular play at the handle or speed reduction gear when changing the sense of movement of the window, and to prevent the cables escaping from the guide channels.
The redirection means carry a channel. The channel is a figure of revolution about a geometrical axis X, and a cable run slides in this channel. The redirection means comprises a supporting element, a redirection ring and a helical spring located between the supporting element and the redirection ring. The helical spring exerts a cable stretching effort on the redirection means. The redirection ring comprises an axis of symmetry. The supporting element comprises a shaft that is firstly rotatably mounted on a retention plate. This shaft and the redirection ring are offset. The supporting element is rotated in order to stretch the cable. Once a desired cable stretching is obtained, the shaft is riveted to the retention plate.
This window lifter has several drawbacks. Among them, the use of a spring complicates notably the assembly of the window lifting mechanism.
Document WO-A-95 00734 describes another window lifting mechanism. This window lifting mechanism comprises a cable guide member rotatably mounted to a body. The guide member seats and guides a cable. A spring biases the guide member in a rotational direction in order to tension the cable. The window lifting mechanism also comprises ratchet means coupling the cable guide member and the body. The ratchet means are responsive to a very slow change in the operating rotational position of the guide member in one rotational direction, over multiple cyclic movements of the line, to move from one ratchet position to a next ratchet position comprise an engagement member.
This window lifter has several drawbacks. Among these drawbacks, this window lifting mechanism does not lock the guide member on the body. Indeed, the guide member is able to move during a window movement, which can cause noise.
Both window-lifting mechanisms require complex and expensive elements. These window-lifting mechanisms also require complicated and tedious assembly.
There is a need for a window lifter that solves one or several drawbacks of this window lifter.
An object of the present invention concerns a window lifter comprising:
a cable;
a window linkage driven by the cable;
a fixed device;
a cable redirecting device:
rotatably mounted on the fixed device;
adapted to automatically lock onto the fixed device upon reaching a predetermined angular position;
having a cable guiding portion (12) which is not a figure of revolution about the axis of rotation relative to the fixed device.
According to another aspect of the invention, the cable-redirecting device is adapted to be elastically deformed before reaching the predetermined position.
According to a further aspect of the invention, the fixed part provides a protruding portion, elastically biasing the cable-redirecting device before the redirecting device reaches the predetermined position.
According to a still further aspect of the invention, the protruding portion is formed by stamping or deep drawing of the fixed device.
According to another aspect of the invention, the protruding portion is a slanted ramp.
In another embodiment, the fixed device provides an aperture, the cable redirecting device includes a lug adapted to be housed in the aperture.
According to a further aspect of the invention, the fixed device comprises a plurality of apertures adapted to house said lug.
In another embodiment, the redirecting device is rotatably mounted on a shaft integral with the fixed device.
In a further aspect of the invention, the shaft is formed by stamping or deep drawing of the fixed device.
In another embodiment of the invention, the fixed device provides a cut-out, the cable-redirecting device provides a protrusion, the cut-out (33) and the protrusion being shaped to allow the insertion of the protrusion through the cut-out in a predetermined relative angular position and to provide rotation guiding to the inserted protrusion for other relative angular positions.
According to a further aspect of the invention, the protrusion provides a cylindrical portion, a radially-oriented pin, located at the distal end of the cylindrical portion.
According to an aspect of the invention, the window lifter further comprises a rail on which the window linkage is slidably mounted.
In another aspect of the invention, the cable-redirecting device carries a channel which is substantially a figure of revolution and in which a cable run slides.
In an aspect of the invention, the cable-redirecting device has the form of a sector of a circle.